Can you please elaborate, why such a formula does not work for Logical
interfaces?

Thanks and rgds, Murthy

Jochen Friedrich wrote:

Hi Murthy,

> Let us consider an equipment having the entities, rack, shelves, slots,
> cards, ports. Let us assume, maximum number of SNMP interfaces (ex;
ATM
> interface, ADSL line interface, ADSL channel interface) supported
per
> slot is X. Then, we can device a formula to find out ifIndex of an
> Interface uniquely as follows;
>
> ifIndex=<rack #> <shelf #> <slot #> <interface # within
the slot. 0 to
> X>
>
> With this formula, one get same ifIndex all the time for a particular
> Interface.

That might work for physical interfaces but will definitely fail for
logical ones (like loopback, tunnel, ELAN, trunk interfaces etc).